Subject: Re: [PATCH v2 3/6] imap-send: replace auto-probe libcurl with hard dependency

From: Junio C Hamano <[email-masked]>
Date: Thu, 02 Feb 2023 11:33:02 -0800

>  imap.authMethod::
>  	Specify authenticate method for authentication with IMAP server.
> -	If Git was built with the NO_CURL option, or if your curl version is older
> -	than 7.34.0, or if you're running git-imap-send with the `--no-curl`
> +	If you're running git-imap-send with the `--no-curl`
>  	option, the only supported method is 'CRAM-MD5'. If this is not set
>  	then 'git imap-send' uses the basic IMAP plaintext LOGIN command.

OK.

> diff --git a/Documentation/git-imap-send.txt b/Documentation/git-imap-send.txt
> index f7b18515141..202e3e59094 100644
> --- a/Documentation/git-imap-send.txt
> +++ b/Documentation/git-imap-send.txt
> @@ -44,8 +44,7 @@ OPTIONS
>  
>  --no-curl::
>  	Talk to the IMAP server using git's own IMAP routines instead of
> -	using libcurl.  Ignored if Git was built with the NO_OPENSSL option
> -	set.
> +	using libcurl.

Hmph, let's read on to resolve "when built with NO_OPENSSL, giving
--no-curl now errors out or do something else? do we need to? why?",
which was my knee-jerk reaction.

> diff --git a/INSTALL b/INSTALL
> index d5694f8c470..d9538bbcb45 100644
> --- a/INSTALL
> +++ b/INSTALL
> @@ -129,13 +129,13 @@ Issues of note:
>  	  itself, e.g. Digest::MD5, File::Spec, File::Temp, Net::Domain,
>  	  Net::SMTP, and Time::HiRes.
>  
> -	- git-imap-send needs the OpenSSL library to talk IMAP over SSL if
> -	  you are using libcurl older than 7.34.0.  Otherwise you can use
> -	  NO_OPENSSL without losing git-imap-send.
> +	- git-imap-send needs libcurl 7.34.0 or newer, in addition
> +	  OpenSSL is needed if using the "imap.tunnel" open to tunnel
> +	  over SSL. Define NO_OPENSSL to omit the OpenSSL prerequisite.

"if using the imap.tunnel to open a tunnel over ssl"?
because I think there are some grammo there.

"to omit the OpenSSL prerequisite" -> "if you do not need it"?
because the original sounds like losing prereq without any penalty.

>  	- "libcurl" library is used for fetching and pushing
>  	  repositories over http:// or https://, as well as by
> -	  git-imap-send if the curl version is >= 7.34.0. If you do
> +	  git-imap-send. If you do
>  	  not need that functionality, use NO_CURL to build without
>  	  it.

OK.

> diff --git a/Makefile b/Makefile
> index 45bd6ac9c3e..b08a855198c 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -773,7 +773,9 @@ PROGRAMS += $(EXTRA_PROGRAMS)
>  
>  PROGRAM_OBJS += daemon.o
>  PROGRAM_OBJS += http-backend.o
> +ifndef NO_CURL
>  PROGRAM_OBJS += imap-send.o
> +endif

Nice.

> @@ -1592,6 +1593,7 @@ ifdef NO_CURL
>  	REMOTE_CURL_ALIASES =
>  	REMOTE_CURL_NAMES =
>  	EXCLUDED_PROGRAMS += git-http-fetch git-http-push
> +	EXCLUDED_PROGRAMS += git-imap-send

OK.

> @@ -1617,19 +1619,9 @@ else
>  	REMOTE_CURL_NAMES = $(REMOTE_CURL_PRIMARY) $(REMOTE_CURL_ALIASES)
>  	PROGRAM_OBJS += http-fetch.o
>  	PROGRAMS += $(REMOTE_CURL_NAMES)
> +	IMAP_SEND_LDFLAGS += $(CURL_LIBCURL)

OK.  That is a natural consequence of losing USE_CURL_FOR_IMAP_SEND
conditional, which is good.

> @@ -2786,7 +2778,7 @@ endif
>  git-%$X: %.o GIT-LDFLAGS $(GITLIBS)
>  	$(QUIET_LINK)$(CC) $(ALL_CFLAGS) -o $@ $(ALL_LDFLAGS) $(filter %.o,$^) $(LIBS)
>  
> -git-imap-send$X: imap-send.o $(IMAP_SEND_BUILDDEPS) GIT-LDFLAGS $(GITLIBS)
> +git-imap-send$X: imap-send.o http.o GIT-LDFLAGS $(GITLIBS)

And this too is a natural consequence of http.o that serves as a
linkage between us and libcURL being always used.  Good.

> diff --git a/imap-send.c b/imap-send.c
> index b7902babd4c..26f8f01e97a 100644
> --- a/imap-send.c
> +++ b/imap-send.c
> @@ -30,20 +30,10 @@
> ...
> +static int use_curl = 1;

OK.

>  int cmd_main(int argc, const char **argv)
>  {
> @@ -1531,12 +1519,7 @@ int cmd_main(int argc, const char **argv)
>  	if (argc)
>  		usage_with_options(imap_send_usage, imap_send_options);
>  
> -#ifndef USE_CURL_FOR_IMAP_SEND
> -	if (use_curl) {
> -		warning("--curl not supported in this build");
> -		use_curl = 0;
> -	}

Naturally ;-)

> -#elif defined(NO_OPENSSL)
> +#if defined(NO_OPENSSL)
>  	if (!use_curl) {
>  		warning("--no-curl not supported in this build");
>  		use_curl = 1;

In the original, this part reached iff we had USE_CURL_FOR_IMAP_SEND,
so "if we are using curl and do not have openssl, then --no-curl is
rejected and we forced use of curl" was how the original behaved here.

Here, we always link with curl, so the updated code is doing exactly
the same thing.  Good.

But then the documentation change above that puzzled me was there
not because it was needed to match updated behaviour (the behaviour
stayed the same).  So was it meant as a documentation improvement?

> @@ -1580,10 +1563,8 @@ int cmd_main(int argc, const char **argv)
>  	if (server.tunnel)
>  		return append_msgs_to_imap(&server, &all_msgs, total);
>  
> -#ifdef USE_CURL_FOR_IMAP_SEND
>  	if (use_curl)
>  		return curl_append_msgs_to_imap(&server, &all_msgs, total);
> -#endif

Naturally.

>  	return append_msgs_to_imap(&server, &all_msgs, total);
>  }

Looking good.  Thanks.